Description:

Patients presenting with anterior ST-segment elevation myocardial infarction (STEMI) are at high risk for adverse outcomes, despite undergoing primary percutaneous coronary intervention (PPCI). Intra-aortic balloon pump (IABP) is frequently employed in patients with STEMI who either present or tend towards cardiogenic shock. The current trial sought to study if routine IABP use in patients with anterior STEMI who were not in cardiogenic shock would result in reduced infarct size and improved clinical outcomes.

Hypothesis:

Routine IABP use in patients with anterior STEMI not in cardiogenic shock would be associated with a reduction in infarct size, as assessed by cardiac magnetic resonance imaging (CMR) 3-5 days following PCI.

Concomitant Medications:

Principal Findings:

A total of 337 patients were randomized, 161 to IABP prior to PCI and 176 to standard PCI. Baseline characteristics were fairly similar between the two arms. A total of 15 patients crossed over from standard PCI to IABP, mainly due to development of sustained hypotension or cardiogenic shock. About 48% of the patients were Caucasian, and 45% Asian. About 19% had a history of diabetes mellitus, 29% hypertension, and 32% were current nicotine users. The median systolic blood pressure/diastolic blood pressure on admission was 131/80 mm Hg, with a median heart rate of 75 bpm. The majority of patients had ≥6 mm ST elevation in the anterior leads. PCI was successfully performed in 94% of the patients, and the left anterior descending artery (LAD) was the target vessel in 97.6% of the patients. A proximal LAD lesion was noted in 63% of the patients. About 65% of the patients had Thrombolysis In Myocardial Infarction (TIMI) 0 flow at baseline, and 94% had TIMI 3 flow at the end of the procedure. The median door-to-first device insertion time was slightly higher in the IABP arm (77 vs. 68 min, p = 0.04). Aspiration thrombectomy was performed in about 35% of the patients. Bare-metal stents were used in 53.4% of patients. IABP was continued for >24 hours in all patients, and the median duration of IABP use was 22.1 hours.

Interpretation:

The results of the current trial indicate that routine IABP use before PCI in patients with anterior STEMI who are not in cardiogenic shock is not associated with a reduction in infarct size or improved clinical outcomes at 6 months, as compared with standard of care PCI, with IABP use reserved as “bailout” for cardiogenic shock/unsuccessful PCI. However, IABP requirement is relatively common in these patients, with a crossover rate of about 8-9% observed in this trial. Further long-term data are awaited. These results are similar to those noted in the BCIS-1 trial in patients undergoing high-risk PCI.